text: The basic function of PDRCs is to be high in both solar reflectivity (in 0.4–2.5 µm) and in heat emissivity (in 8–13 µm), to maximize "net emission of longwave thermal radiation" and minimize "absorption of downward shortwave radiation." PDRCs use the infrared window (8–13 µm) for heat transfer with the coldness of outer space (~2.7 K) to radiate heat and subsequently lower ambient temperatures with zero energy input.
  PDRCs mimic the natural process of radiative cooling, in which the Earth cools itself by releasing heat to outer space (Earth's energy budget), although during the daytime, lowering ambient temperatures under direct solar intensity. On a clear day, solar irradiance can reach 1000 W/m with a diffuse component between 50 and 100 W/m. The average PDRC has an estimated cooling power of ~100–150 W/m. The cooling power of PDRCs is proportional to the exposed surface area of the installation.